How do you get a json file (ABI) from a known contract address?

Question

I want to watch a Solidity contract using the Mist browser. I know how to do that and it needs the address and the json. I have the address, but I don't have the json. I do have the source code.

Can I generate the json from the source code and/or the Ethereum address?

Answer 1

The JSON is called an ABI.

You do need the source code, as you have, and one way to get the ABI is to paste it in Remix IDE, compile it, and then click the 'ABI' button to copy the ABI into your clipboard.

Answer 2

If the contract is verified in Etherscan, the following script fetches the ABI and saves it to a JSON file. Use it like

$ python fetch_abi.py <contract address> -o <target JSON file>

fetch_abi.py

#!/usr/bin/python
import argparse
import requests
import json

# Exports contract ABI in JSON

ABI_ENDPOINT = 'https://api.etherscan.io/api?module=contract&action=getabi&address='

parser = argparse.ArgumentParser()
parser.add_argument('addr', type=str, help='Contract address')
parser.add_argument('-o', '--output', type=str, help="Path to the output JSON file", required=True)

def __main__():

    args = parser.parse_args()

    response = requests.get('%s%s'%(ABI_ENDPOINT, args.addr))
    response_json = response.json()
    abi_json = json.loads(response_json['result'])
    result = json.dumps({"abi":abi_json}, indent=4, sort_keys=True)

    open(args.output, 'w').write(result)

if __name__ == '__main__':
    __main__()

Answer 3

Here is how you get the abi by using your local solc compiler:

solc filename.sol --abi

You also need the bin code to deploy the contract, which you can get as follows:

solc filename.sol --bin

If you want a solc combined output (e.g. for parity), where bin is part of the abi json string, use this:

solc filename.sol --combined-json abi,bin

Answer 4

EDIT

On Compile tab (right top menu) just click on Details.

---

OLD METHOD

In the new version of Solidity Browser you can find Interface value clicking on Contract details (bytecode, interface etc.)

Answer 5

Go to EtherScan > enter the contract address > click on the Code in the tab section heading > Scroll down to find the Contract ABI > click on the Copy icon to copy it

Answer 6

You can get ABI json from etherscan API like below.

var Web3 = require('web3');
var web3 = new Web3(new Web3.providers.HttpProvider());
var version = web3.version.api;
        
$.getJSON('https://api.etherscan.io/api?module=contract&action=getabi&address=0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359', function (data) {
    var contractABI = "";
    contractABI = JSON.parse(data.result);
    if (contractABI != ''){
        var MyContract = web3.eth.contract(contractABI);
        var myContractInstance = MyContract.at("0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359");
        var result = myContractInstance.memberId("0xfe8ad7dd2f564a877cc23feea6c0a9cc2e783715");
        console.log("result1 : " + result);            
        var result = myContractInstance.members(1);
        console.log("result2 : " + result);
    } else {
        console.log("Error" );
    }            
})

Answer 7

Simple go to http://remix.ethereum.org/ and paste the source code of the contract. Click of Start compile and after a few seconds or so, your contract is processed. Click on detail button (found at the top-right). On the popup, you would find the ABI, METADATA, BYTECODE, etc